Uptake and Absorption of Selected Chemopreventive Agents in Experimental Animals The objective is to develop and standardize assay protocols for selected chemopreventive agents which arf highly sensitive, quantifiable, and reproducible for serum (or plasma) and tissue measurements. Measure the concentration of selected chemopreventive agents in blood serum from rats and mice fed standardized diets containing various levels of chemoprevention agents. Serum levels of agents is being measured using tissues received from other sites from studies in progress. Protocols are being developed for the measurement of chemopreventive agents in serum or tissue extracts that are sensitive and quantitative. Methodology is being characterized for sensitivity, linear range, within and between day to day coefficient of variation. Animals (mice, rats, hamsters) are being fed agents at two levels in diets Blood samples are collected and serum extracted from 10 animals at baseline and after two weeks of feeding in each different dose group. The samples are being analyzed to determine agent concentration (muM) in serum extracted in early morning. The variance and standard deviation of the mean values are being determined. The absorption ratio is being determined by comparing the serum concentration versus the food concentration. At least two tissues for each agent are being determined and analyzed.